In ball-hitting sports generally, players want to impart to the ball as much momentum as possible, either so that it may pass by an opponent quickly, before the opponent has a chance to react, or so that the ball travels a long distance toward a goal. More particularly, in sports such as baseball and golf, one important aim is to hit the ball as far as possible, and a player's capability to do this is an important source of the player's satisfaction.
One way to enable a player to hit a ball farther or harder is to improve on the hitting characteristics of the hitting implement. In some sports, such as golf and tennis, such improvements are accepted and, to an ever increasing extent, demanded by players. Baseball on the other hand, much more than other sports, is infused with tradition and nostalgia. Fans and players alike are generally accustomed, therefore, to the characteristics of the classic solid, ash-wood bat and have not tended to think in terms of altering those characteristics. An important reason for, as well as cause of, this acceptance is the major leagues' insistence in its rules on the use of such all-wood bats.
However, hollow metal bats have been employed by the minor leagues, especially in practice, and by people just having fun. But the prior art in metal bats has, consonant with the above observation, focused on attempts to emulate the performance of the wood bat rather than to improve thereupon. Particularly, these emulating efforts have been directed to the material of which the bat is constructed, which includes metal, plastics and composites (see New Scientist, supra, at 27; Jones, U.S. Pat. No. 4,546,976), the weight of the bat (see Bahill and Karnavas, "The Ideal Baseball Bat", New Scientist, Apr. 6, 1991, at 26), the distribution of the weight of the bat (e.g, Noble, U.S. Pat. No. 4,834,370), the surface elasticity of the bat (so-called "trampoline effect;" see "Wood-Composite Baseball Bats Take the Field," supra) and the pressure inside a hollow bat (e.g, Foreman, U.S. Pat. No. Re. 31,811).
Other sports, such as golf and tennis, are not so bound by tradition and greater creativity has generally been in evidence in the design and re-design of the implements employed for hitting the ball. However, improving the performance in any of these implements has been a difficult technical challenge, beginning with the difficulty in analyzing the dynamics of the implements having various proposed structures simply to understand what potential structural features to employ, or reject. This can be especially appreciated when one realizes that the performance improvements sought can be relatively small and still provide a player using the improved implement with a noticeable and highly desirable edge over his or her opponents, or a noticeable and highly satisfying personal performance improvement.
Researchers have tried to analyze the mechanics of the baseball-bat interaction and the dynamics of the baseball bat, and have noted great difficulties. In "The Dynamical Theory of the Baseball Bat", American J. of Physics, 60 (2), February 1992, at 172, L. L. Van Zandt proposes a mathematical model of a wooden baseball bat which demonstrates so-called normal modes of bending of the bat. "The irregular shape [of the baseball bat] precludes any possibility of accurate analytical solution for a realistic model . . . [, accordingly,] the tool for study of the bat is the computer." Id. at 173. The author concludes that the bending modes of the bat contribute significantly to the range of the flight of the ball and states that "it is possible to imagine tuning the bat to produce optimum hitting performance" by adjusting the normal mode bending frequencies, but fails to suggest any way of doing so. Further, "the normal modes can be strongly influenced by relatively minor changes in the cross-sectional contours of the bat." Id. at 180. Regarding the trampoline effect, it is noted that "there is no convincing scientific proof of what's happening in the ball-bat collision. " "Wood-Composite Baseball Bats Take the Field," supra at 45. Indeed, the dynamics of baseball is regarded by many as a "black art." "Wood-Composite Baseball Bats Take the Field," supra at 44.
Probably equally as a result of the great weight of tradition and the technical difficulties in characterizing and therefore improving on the dynamics of the baseball bat-baseball interaction, baseball bat performance has not been significantly advanced over that of the classic ash-wood bat. Therefore, the multitude of players who desire as all players do to "hit the ball out of the park" but who do not have the athleticism of a major league baseball player continue to want for more in the black art of baseball bat design.
Accordingly, there is a need for a baseball bat having a tunable shaft that provides for tuning the baseball bat for achieving peak hitting performance superior to baseball bats heretofore known in the art.